90 kdx200 still running badly

[gator kdx]

I have adjusted and checked all the easily accessible engine parts. My bike still has very little power - 1st gear is useless (gets to maybe 5-8mph) and no gear has the power to pull the front wheel up. I just put in new reeds and am running a 150 main and 55 pilot, unsure about needle. I did a compression test and get a consistent 150.

I replaced the valve needle and re-adjusted the float level but the carb still is constantly overflowing. The bike runs extremely rich and I suspect that this may be the majority of the problem.

Also, I pulled the pipe off and checked the kips - as much as I could see. The shaft coming out of the case turns at about 1/2 throttle as I think it's supposed to. However, when I look at the side valves with the motor running (cant see the main because of the exhaust) they are bouncing all over the place.

If anybody has any ideas or suggestions please let me know. Trying to figure this thing out is making me crazy, but I don't want to give in and take it to a shop.

 

[jpm200]

To check that the kips are operating correctly, take the pipe off and without starting the motor look into the ports while pulling the actuator rod.
All valves should open and close together. If they don't then there is a problem.
Even if they operate correctly, they may slip under load.
The problem is normally with the LH valve. Try to hold it stationary while pulling the actuator rod see if the rack jumps teeth. Do the same with the RH valve.

 

[gator kdx]

Thanks for the quick reply.

I checked it the way you mentioned and moving the actuator doesn't move either of the side valves. The center valve does move with the actuator arm, but seems to slightly over-rotate.

Would this explain why it is running so rich? or should I keep looking?

I might get a compression test on the bottom end to find if the crank seals are leaking, but am trying to avoid the 1 1/2 hrs labor.

 

[jpm200]

It the side valves don't move then the gears are stripped or the shaft is snapped.
Forget compression, crank seals, jetting etc. Drain the coolant pull the head and replace the valves.

 

[canyncarvr]

1. No it doesn't explain why it's so rich.

This was one thread I forgot to post something else to that may be pertinent..glad you reposted.

Afore I forget..make sure your vent tubes on the carb are clear. Also that the checkvalve on your tank cap works.

That said, what does 'constantly overflowing' mean? If your float level is correct and 'replaced valve needle' refers to the inlet needle that is activated by the floats, there is NO WAY you should still be 'constantly overflowing' if that system is working the way it should.

I presume your floats actually float? They aren't full of fuel, are they.

None of that part has anything to do with your subport drums not rotating. The fuel overflow notwithstanding, if those are stuck 'open' (in hi-rev position), you're bottom end is going to stink.

That's a classic symptom of a bad KIPS....no bottom end.

Still...that's not related to 'constantly overflowing'.

Ya gots at least two things going on here.

BTW...earlier kdxs are notorious for KIPS problems from what I've read. Talk to fredette if you can about parts if you need 'em. Seems he might have something made from a better metal? Not sure about that. Seems I read that someplace. In any case, I'll bet'cha he'd have the parts you need to fix the stripped gear issue you pretty obviously have.

 

[gator kdx]

I pulled the top end off yesterday and today I went to my dealership and ordered all new exhaust valve parts. Hopefully that will help with alot of the poor performance issues.

Also, when I looked at the cylinder I noticed a crack on one of the intake ports. Looks like I'm going to have to get it machined and plated.

As for the carb, I submerged the float for several hours last week and it still floated afterwards. I ordered a new float today also, in case maybe the old one was sticking somehow I couldn't see.

Hopefully this will take care of the majority of my problems because it's starting to get pretty expensive.

Thanks for all the input.... if there are any more suggestions or ideas I'm always listening.

 

[spikes]

IF YOUR FLOATS STILL FLOAT YOU DON`T NEED NEW ONES. SPEND THE MONEY ON A NEW FLOAT NEEDLE. YOU CAN MAKE YOUR OWN POWER VALVES IF YOU HAVE ACCESS TO A LATHE, I MADE MINE OUT OF PB1. YOU CAN ALSO USE OIL-LIGHT BRONZE. MEASURE UP THE OLD VALVE AND TURN UP THE BASIC PROFILE. MAKE A HSS CUTTER PROFILED OFF THE OLD GEAR TEETH AND LOCK THE LATHE SPINDLE IN 12 EQUAL POSITIONS, INDEX THE SADDLE LEFT TO RIGHT TURNING THE CROSS SLIDE IN A **** HAIR EACH STROKE UNTILL YOU BOTTOM OUT YOUR TOOTH CUTTER PROFILE. THEN INDEX THE SPINDLE 1/12 AROUND AND SAME AGAIN. SET UP YOU NEW VALVE IN THE CYLINDER AND SCRIBE AROUND INSIDE THE BOOST PORT, THEN GRIND OUT THE VALVE INSIDE THE SCRIBED LINE. SEE EASY JAPANESY!

 

[gator kdx]

I tried salvaging the float for probably 5 hours but whoever worked on it before me-I've only had the bike for about a month- really mangled it up.

It's twisted so badly that I think the metal is stretched slightly.

Also, I did check all the vents and they are all flowing freely. When I was testing it the other day, I ran it without vent tubes - but that shouldn't matter, should it?

To avoid buying a float level gauge I rigged up an old spark plug boot and a clear hose. It was a minor pain in the ass since the main jet sits in the bottom of the drain plug. I ran the hose up the side of the carb hoping that physics would hold and I could get an idea of where float valve was actually shutting off.

Anyhow, I hooked it up and filled up the carb through the gas intake and the level seemed to consistently stop right around the mating surface of the bowl and carb body. I decided that was a bit high so lowered the float until the level in the hose stopped at about 3mm below the top of the bowl.

I figured if anything this was maybe too low and the motor would starve, but when I ran the bike for a few minutes and then stopped it, a near steady stream of gas came out the carb overflow until i turned off the gas petcock.

After I adjusted the float using my makeshift gauge, I looked at it to see how close to parallel the floats were to the bowl surface - and it appeared the the floats were set way too low.

Any and all suggestions are welcome. Thanks for all the replies so far. If anybody knows where the fluid level should stop with my makeshift level gauge please help me out.

 

[jamin326]

your pilot jet of a 55 seems a little rich i ran a 48 in my 91 KDX200